What Should be the Size of My Pet Door?

Before getting a new pet door, many people often wonder what size would be a perfect fit for their animal. Some people do not take the requirements into account and later they have to suffer the consequences of their mistake.

Let’s talk about selecting a right-sized door for your cute pet.


Measure your pet’s height from the lowest point (ground) to the highest point of its back. You can measure its perfect width by letting it walk through a small space. If your animal is comfortable in going through that hole, then that is the minimum space it needs to move in and out.

Animals, especially cats, don’t like to do things that are uncomfortable for them. So, make sure that your pet door does not restrict the movement of your animal.

While choosing a flap, you should consider the mounting height of the pet door. This distance can be called as the Step Over.

Calculate the height of the flap’s top by adding the Step Over to the flap’s height. Remember to keep this measurement at least 1 inch taller than your pet’s height.

An animal, especially an old one, will find it easier to go through a pet door that has a lower Step Over. A 3 to 5 inches Step Over can be great for dogs, but it depends on the body type of the animal.

Selecting the Right Size of a Pet Door

You can follow this guide to make sure that your pet is comfortable with the new pet door.

  • Measure your pet’s height from its feet to shoulder.
  • The door flap’s top portion needs to be at least 1″ above the back of your animal.
  • The flap’s top = Step Over + flap’s height
  • Also consider the width of your animal to determine the right size of your pet door.

After deciding on the size of a pet door, you can choose a same-sized box to check whether or not your calculations were correct. If your pet is comfortable while crossing the open-ended box, then you have determined the accurate size.

In case of miscalculations, you can make adjustments accordingly. Also, take into account the Step Over. Your pets should be comfortable while stepping in and out of your house.

Multiple Pets

If you have more than one animal in your house, you can determine the ideal size of a pet door by measuring the height and width of the largest pet.

However, you also have to make sure that the smallest animal in your house is not having any difficulty in entering or leaving the house via a pet door due to a high Step Over.

Whatever option you decide to pursue, keep in mind that a “mock” object can help you save from buying a wrong-sized pet door.